Switch with pole plates having a separation of non-magnetizable material



Aug. 24, 1965 B. GRIESEN 3,202,783 SWITCH WITH POLE PLATES HAVING A SEPARATION OF NON-MAGNETIZABLE MATERIAL Filed Feb. 16, 1962 T 32 45Al7 lll62292l IO INVENTOR Bel-flu Grie en WIS: M Can/Maw ATTORNEYS United States Patent i" 1 Claim. in. 200-s7) The invention concerns a high-voltage on-load disconnecting switch comprising: a stationary barrel-shaped member of insulating material, in which two fixed contacts are accommodated; a detachable switch cap of insulating material, which can be pushed on the bar-,

rel and in which are present two movable contacts connected to form a conductive bridge, said contacts coming into contact with the fixed contacts and interconnecting the latter when the cap is pushed on the barrel; a permanent magnet system, mounted in the barrel between the fixed contacts and comprising two pole plates perpendicular to the plane through the fixed contacts; and an armature plate of magnetizable material, which is associated with the conductive bridge in the cap and which comes into contact with the pole plates when the cap is pushed on the barrel, and consequently is held by magnetism.

A switch of this kind is known from Polytechnlsch Tijdschrift, col. 14, No. 39-40 of September 23, 1959, pp. 937a-940a.

' When the shortcircuit power of switches of this type is boosted, the force with which the permanent magnet system holds the armature plate in the closed position of the switch has been found to be no longer sufficient considering the occurrence of the intensity of current associated with the higher short-circuit power.

For such an unforeseen case the invention aims at and ensures a higher degree of safety in a simple way.

The diffculty in question is met to a considerable ex;

tent by a feature which initself is constructionally simple,

viz. by designing the unit in such a way that at least in the part of. each of the pole plates which is turned towards the armature plate a separation of nonmagnetizable material, perpendicular to the plane of the pole plate is provided in at least one place.

No satisfactory explanationof this surprising effect has yet beenfound. The tests carried out seem to indicate that it is not necessary for theseparation toextend as far as the end of each of the pole plates which is turned away from the armature plate.

The invention will be explained more fully with reference to an embodiment shown by way of example in the drawing.

This embodiment concerns a single-phase switch. The invention is by no means confined to this.

FIG. 1 illustrates a switch according to the invention in the closed position, cut through along the line I'I in FIG. 2.

FIG. 2 is a cross-section along the line II-II in FIG. 1.

The switch according to FIG. 1 comprises a stationary member located on the left and a movable member located on the right. These members will be discussed successively.

The stationary or barrel-shaped member is equipped with two fixed contacts 1. Each of these consists of a central part 2 and an outer part 3. Between these two parts is a cylindrical insulating switching chamber 4. The two fixed contacts 1 and the two switching chambers 4 together are surrounded by a sleeve 5 which, like the part in which the fixed contacts 1 are incorporated, is

3,202,783 Patented Aug. 24, 1965 made of an electrically high-grade insulating material, such as a moulding resin. Between the two fixed contacts 1 and the two switching chambers 4, also incorporated in the insulating material, is a permanent magnet system consisting of two ferromagnetic pole plates 6, separated by a number of permanent magnets 7 polarized in the same direction.

From the end which cooperates with the armature plate 14 of magnetizable material to be discussed below, each of the pole plates is subdivided over part of its length into two equal parts 6 and 6 In the narrow space between said two equal parts a strip of nonmagnetizable material 8 is present, FIG. 2.

The free ends .of the parts 6 and 6 of the two pole plates 6 project slightly beyond the adjacent insulating material. In consequence of this-a ferromagnetic armature plate 14 cooperating therewith can be contacted directly with the pole plates.

The movable member of the switch consists of a cap 9 of insulating material, such as a moulding resin. This cap 9 can be fitted on or removed from the stationary member of the switch in a way not specified, e.g., with the aid of a detachable handle pushed on it. With a view to the accommodation of the handle the cap 9 is profiled at its closed end (to the right in FIG. 1).

Incorporated in the cap 9, at a distance from each other that is equal to that between the fixed contacts 1, are two electrically interconnected metal sleeves 10, which are rigidly connected with the cap. Each of the metal sleeves 10, on the side turned towards the axis of the switch, reckoned from the closed side of the cap over about one half of its length, is provided with a fairly wide axial slot 11. Connected with this via a discontinuous transistor 13 is a narrower slot 12. The transistor 13 between the two slots serves as an abutment for the armature plate 14.

Between the two sleeves 10 and perpendicular thereto 1 extends the armature plate 14 of ferromagnetic material.

This plate can be displaced in the longitudinal direction of the sleeves 10 relative to said sleeves and thus moves through the axial slots 11.

Near its free end each of the sleeves 10 is provided on the inside with a collar 15. Located between the collar 15 and the armature plate 14 in each of the sleeves 10 is a helical spring 16, which serves as a disconnecting spring in a way to be described below. By the disconnecting spring 16 each of the ends of the armature plate 14 is forced in the direction of the closed part of the cap 9. The armature plate 14 thus rests against the transition 13 of each of the sleeves 10.

The armatureplate 14 carries the two axially movable switching pins 17. On the armature plate 14, concentrically about each of the switching pins -17 on the side of the closed part of the cap 9, a raised portion 18 is present. The part of each of the switching pins 17 which is located in FIG. 1 to the right of the armature plate 14 is provided with a thickening 19 for the insertion of a flexible interconnection 20 of the switching pins 17. Mounted on the part of each of the switching pins 17 which is located to the left of the armature plate is a helical spring 21, of which one end rests under pressure against the armature plate and the other end against an outer collar 22 of the corresponding switching pin. These helical collar 21 serve as contact-pressure springs.

In the opened position of the switch the parts of the movable member take up a relative position in which the disconnecting springs 16 force the armature plate 14 against the transitions 13 in the sleeves 10 and the contact-pressure springs 21 keep the switching pins 17 so far outwards that the thickenings 19 rest against the armature plate 14. The whole of the movable member can be taken off or removed from the stationary member.

the stationary member are then protected in the space surrounded by the sleeve 5. 'When the switch is to be closed, thercap 9 is pushed on the sleeves. This movement results after some time in the free end of each of the metal sleeves 10 coming into contact with the outer part 3 of the corresponding fixed contact 1. 'In consequence of this the circuit between the two fixed contacts 1 is closed. The free end of each of the switching'pins 17 is now not yet in contact with the central part2 of the corresponding fixed contact 1.

When the cap 4 9 is pushed further over the sleeve 5,

'shortly afterwards the free end of each of the switching pins 17pcomes'into contact with the corresponding central part 2 of the fixed contact 1. When the cap is moved furtherstill, the helical springs 21 are tensed by the armajture plate 14, which is kept forced by the disconnecting springs 16 against the transitions 13 in the sleeves, 10,

which are fixed in the cap 9. .The switching pins 17 1 therefore areforced against the fixed contacts by means of the increasedttension of said springs 16. The springs 21 act as contact-pressure springs. If the switch is to be closed altogether, the cap 9 has to be pushed on the sleeve 5 until the armature plate 14 comes into'contact with the pole plates 6. The switch is then in the switch-on 1 position. It remains in thisposition because the armature plate 14 is held by the parts 6 and 6 of each of I the pole plates 6 under the influence of the permanent magnets 7.] Between the raised portions 18 of the armatu're plate 14 and theilower side of the-thickenings 19 of the switching pins 17 a distance is now present which 7 is equal to the length of compression of the contact-pressure springs 21.

The switch is opened by pulling at the cap 9 with the aid of the previously mentioned handle, for instance. The cap 9 then moves backwards and each of the metal sleeves 10 is drawn along, so that itis separatedtfrom the V sleeves MB. This results in the armature plate 14 being pulled off the pole plates 6. As soon as it has moved away from these pole plates an extremely short distance, the force exercised by the parts 6 and 6 of the'pole plates will decreaase substantially to zero. As a result of this, each of the tensed disconnecting springs 16' (and also the contact-pressure springs 21, which are now eased) greatly accelerates the armature plate 14 towards the right. After a short time the raised portions 18 of the armature plate 14 come into contact with the thickenings 19 of the switching pins 17, in consequence of which the end of each of the switching pins is pulled oil the corresponding fixed contact 1 with a jerk. By this means an effective interruption of the circuit in each of the switching chambers is always ensured.

The movement of the armature plate 14 under the action" of 'each of" the disconnecting springs 16 continues until the armature plate has come into contact again with the transitions 13in the sleeves'10. Any arc in each of the switching chambers 'hasthen already been extinguished. p

c When the cap 9 has been removed altogether from the sleeve 5, it may be put aside, with all the parts present therein which are then again in the relative position described in the paragraph with the opening words: In

the opened position of the switch. WhatIclaim is: i v 1 High-voltage on-load disconnecting switch comprising a stationary member of insulating maerial, two fixed contacts provided in'the member, a detachable switch, cap

,outer part 3 of the corresponding fixed contact 1. The L t the pole plate and in the plane through the fixed contacts.

of insulating material adapted to be pushed on the member, two movable contacts mounted in the cap and connected to form a' conductivebridge with said contacts coming into contact' with the fixed contacts and interconnecting the latter when the cap is pushed on the ferromagnetic pole plates arranged perpendicular to the plane through the fixed contacts and separated by at least one permanent magnet, and'an armature plate of magnetizable material associated with the conductive bridge in the cap and which contacts with the pole plates when the cap is pushed on the member and is held by magnetism, and a separation of non-magnetizable material is provided in at least one place at least in the part of each of the pole plates which is turned towards the armature plate and lying perpendicular to the plane of References Cited by the Examiner UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner. a 

